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2 Posts

08-27-2018

DE

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L480 HDMI not working after system recovery

2018-08-27, 9:49 AM

After formatting my harddisk (shame) I renewed my system with very competent help by the hotline. I needed many days to install all my working tools and create my workspaces again. The last point is connecting the second screen (BENQ via DVI, HDMI/DVI adapter at L480), but there is no reaction.

The BENQ tells me "no signal" (physical connection is detected) and Windows OS tells me "no other screen detected".

Today, a BIOS update happened and I hoped, it will work now. So I tried another few hours to get HDMI working, but the error is the same.

I have no idea, how go on, the Lenovo Vantage has no help for HDMI.
May be, I have to ask the hotline again. But before doing so, I ask the community here.

Maybe someone did have the same problem and has found a solution.

Best regards
Robert

 

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2 Posts

08-27-2018

DE

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Re: L480 HDMI not working after system recovery [solved]

2018-08-28, 8:31 AM

When I searched Internet for problems concerning HDMI and Lenovo, I found a lot of unbelievable solutions. Being an engineer, I did not follow them. But after updating "anything" (BIOS, Intel drivers, ...) without success, I started testing some unbelievable solutions.

 

There was a hint, that some HDMI cables or adapters have a short plug and the connector at the Lenovo notebook ist not filled enough with all pins. In fact I detected, that my DVI/HDMI adapter has a shorter plug than a typical HDMI cable from my TV. So I took another screen with direct HDMI input (iiyama) and connected it with my notebook.

After restarting the notebook, the screen was detected and worked as expected.

Than I changed to the old equipment (BENQ with DVI, DVI cable and HDMI/DVI adapter at the notebook) and it worked also.

Ok, so far I can explain the behaviour.

 

But after rebooting the notebook, the old equipment continued working. That I did not expect, because the testing of anything the days before has shown, that this equipment does not work.

May be someone has a better idea, but I have now only one reasonable explanation:

 

It seems to be, that Lenovo notebooks (resp. the OS, here Win 10 Pro) need a reliable all pin connection at HDMI "only one time after installation of OS". Then the connection is marked (somewhere) and it works also with a worse connection, may be not needing "all pins" or or simply with a "less quality connection".

 

I think, we will have more such mistakes in the future with "smart" software, because the software is only as smart as the programmer. And the problems, which the programmer does not know, can never be solved with the smart (automatic) software. So a simple command like "do switch on HDMI" started by the user would solve all the "unbelievable" problems.

 

Added:

It is not a matter of the OS. It must be something in the BIOS or even with the hardware. Because I had the same behavior with Linux Mint. I did not see the second screen the last days, also with Linux. And now, everything is ok also with Linux after using another connection via HDMI one time.

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29 Posts

12-15-2017

CN

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Re: L480 HDMI not working after system recovery [solved]

2018-08-29, 9:00 AM

Hi,Can I know S/N of this L480 machine and the length of HDMI cable used, so we can use the same PN planar for duplication

 

Moderator note: please use the forum's private message feature when exchanging serial numbers.  They are subject to abuse and should be kept out of public view.

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